The Lowe Oculocerebrorenal Syndomre (McK #309000) is an X-linked disorder characterized by mental retardation, congenital catracts, renal tubular dysfunction in childhood and progressive renal failure in adulthood. We have found 23 mutations, three of which have been seen in more than one unrelated family. The work is continuing in order to expand our database of mutational changes in OCRL and to correlate mutational changes to changes in function of the phosphatidylinositol (4,5) bisphosphate 5-phosphatase encoded by the Lowe Syndrome gene.